This invention relates to a refrigeration system of the closed circuit, vapor-compression type, and is related to the invention disclosed in my prior copending application Ser. No. 836,091, filed Sept. 23, 1977 now abandoned.
Refrigeration systems of the foregoing type often have an elongated liquid refrigerant line in the high pressure portion of the circuit, exposed to varying ambient conditions. Because of the pressure drop of a long line and warm ambient temperatures, a portion of the liquid refrigerant may change to vapor during travel before reaching the expansion valve. Where the expansion valve is sized to pass only liquid through its orifice, an insufficient quantity of refrigerant necessary to satisfy the vapor pump or compressor will be passed if there is an excessive amount of vapor in the flow stream of liquid refrigerant upstream of the expansion valve. The expansion valve must therefore be considerably enlarged in orifice size to pass the requisite quantity of refrigerant for maintaining the vapor pump operating under all anticipated conditions. To avoid use of an expansion valve sized to pass the vapor in the liquid flow stream and the problems attendant thereto, pressure boosting facilities are generally utilized to maintain the pressure in the high pressure portion of the circuit at a level above the point at which vapor will form under anticipated varying ambient conditions. Such measures are costly and require higher power consumption for compressor operation.
It is therefore an important object of the present invention to provide an improved refrigeration system of the closed circuit, vapor-compression type which will operate efficiently under varying ambient conditions utilizing an expansion valve sized to pass only liquid refrigerant and without any auxiliary pressure boosting facilities for the high pressure side of the circuit.